So, here is what I did:
I've finally installed the version 16.01 of Code:Blocks and everything works fine (finally!!).
So, the problem was indeed that the compiler - by default - provided in the bundle for Code:Blocks is a 64 bits version, while I was willing to link my codes with a 32 bits library.
This is fine, I should have notice this myself.
However, there remains a problem here:
If you go in the download page of Code:Blocks for the last version 20.03, you can still download a bundle for a 32 bit version, but there is no 32 bits version of gcc that comes with it. There is a mistake here, I think, and this should be said somewhere. No?
In all cases, the problem is solved (although with an old version of Code:Blocks).
Thanks for your help on this.
Cheers, Eric.